Material-mixing apparatus

ABSTRACT

A material-mixing apparatus for mixing feeding ration includes an agitator rotatably mounted in a mixing chamber and adapted to operate submerged beneath a mass of materials to be mixed and having a first plurality of upwardly and forwardly directed paddles and a second plurality of downwardly and rearwardly directed paddles and a screw conveyor adjacent each of opposed sidewalls of the mixing chamber with the screw conveyors being positioned at a higher level than the agitator and having edge portions of a flight thereof below an upper surface of the mass of materials. The agitator and the screw conveyors are rotated at different speeds to thoroughly blend the mass of materials within the mixing chamber.

O United States Patent [151 3,638,920 Davis 51 Feb. 1, 1972 [54]MATERIAL-MIXING APPARATUS Primary Examiner-Robert W. Jenkins [72]inventor. Ramsey H Davis, 626 N. Nettleton, Attornekmishbum Gold andLitman Bonner Springs, Kans. 660l2 [22] Filed: Nov. 27, 1970 ABSTRACT[2}] APPL 93,243 A material-mixing apparatus for mixing feeding rationincludes an agitator rotatably mounted in a mixing chamber and adaptedto operate submerged beneath a mass of materials to [52] U.S. Cl..259/l04, 259/5, 259/2l be mixed and having a first plurality ofupwardly and for- [SI Int. Cl. .1301! 7/04 wardly directed paddles and asecond plurality of downwardly [58] Field of Search ..259/6, I04, 21 41,5 and rearwardly directed paddles and a screw conveyor adjacent each ofopposed sidewalls of the mixing chamber with l 56 References Cited thescrew conveyors being positioned at a higher level than the agitator andhaving edge portions of a flight thereof below an UNITED STATES PATENTSupper surface of the mass of materials. The agitator and the screwconveyors are rotated at different speeds to thoroughly 2,947,524Bridges blend the mass of materials within the mixing chamber. 3,090,6055/1963 Copeland... ..259/l04 3,421,740 1/1969 Behrens ..259/6 X 11Claims, 8 Drawing Figures 2. U 4 f r" mmmmw m2? 3.538.920

SHE! l0? 2 INVENTOR.

BY Ramsey H. Davis ATTORNE Y5 SHEEY 2 [If 2 INVENTOR: Ramsey H. DOVISATTORNEY?) MATERIAL-MIXING APPARATUS The present invention relates tomaterial-mixing apparatus and more particularly to a material-mixingapparatus having an agitator in a lower portion of a mixing chamber anda pair of spaced screw conveyors in an upper portion of the mixingchamber for moving surface materials toward the agitator.

The principal objects of the present invention are: to provide amaterial-mixing apparatus particularly adapted for precision mixing of aplurality of materials having different physical characteristics, suchas weight, size, viscosity, cohesiveness and the like; to provide such amaterial-mixing apparatus operative to collect, mix and deliver athoroughly mixed high quality end product, such as a feeding ration forfarm animals, including cattle and the like; to provide such amaterial-mixing apparatus which is extremely flexible and versatile inmixing various materials conforming to prospective needs and mixing thematerials to conform to a chemical analysis having the proportions ofvarious materials within narrow ranges; to provide such amaterial-mixing apparatus adapted to mix silage, haylage, oatlage,hulls, molasses, high-moisture grain or dry grain, liquid molasses,vitamins, concentrates, medications, minerals and the like to form adesired feeding ration; to provide such a material-mixing apparatushaving an agitator for constantly moving roughages, such as silage,haylage, oatlage and the like from one end of a mixing chamber to theother and constantly raising and lowering same thereby blending saidroughages with grain, liquid molasses, supplements, concentrates,vitamins, minerals and the like with the mixing being accomplishedthroughout the entire mixing chamber and a pair of augers or screwconveyors positioned above and on each side of the agitator to circulateor move the materials within the mixing chamber from one end toward theother thereby constantly blending the materials with feedstuffs beingcirculated by the agitator wherein the augers or screw conveyors breakup bulky roughages by scouring the agitators paddles and creating fastercirculation thereby substantially reducing the required mixing time overprior material-mixing apparatus; to provide such a materialmixingapparatus wherein the agitator is particularly adapted to raise heavyresistant ingredients from a bottom portion of the mixing chamber toinsure uniformly blended materials; to provide such a material-mixingapparatus having a pair of spaced augers or screw conveyors positionedabove and having an agitator therebetween to circulate feedstuffsbetween opposite ends of the mixing chamber and deliver same to theagitator; to provide such a material-mixing apparatus having a mixingchamber and an agitator and a pair of augers or screw conveyors thereinwith the mixing chamber and agitator and screw conveyors cooperating toconstantly circulate the materials to be mixed throughout the entiremixing chamber thereby substantially eliminating dead spots which impairaccuracy in proportioning the materials in the final mix; and to providesuch a material-mixing apparatus which is positive in operation, durablein construction, and particularly well adapted for the proposed use.

Other objects and advantages of this invention will become apparent fromthe following description taken in connection with the accompanyingdrawings wherein are set forth by way of illustration and example,certain embodiments of this invention.

FIG. 1 is a perspective view of a material-mixing apparatus embodyingfeatures of the present invention.

FIG. 2 is a side elevational view of the material-mixing apparatus withportions broken away to better illustrate the mixing members within thematerial-mixing apparatus. FIG. 3 is a transverse sectional view takenon line 3-3, FIG. 2, showing the shape of the mixing chamber and therelative positions of an agitator and a pair of augers or screwconveyors.

FIG. 4 is a front end elevational view of the material-mixing apparatusshowing driving means for rotating the agitator.

FIG. 5 is a rear end elevational view of the material-mixing apparatusshowing driving members for rotating the pair of au- FIG. 6 is anenlarged fragmentary elevational view of an outlet for discharge ofmixed materials from the material-mixing apparatus.

FIG. 7 is an enlarged elevational view'of an upwardly and forwardlydirected paddle of the agitator.

FIG. 8 is an enlarged elevational view, at the same scale as FIG. 7, ofa downwardly and rearwardly directed paddle of the agitator.

Referring more in detail to the drawings:

The reference numeral 1 generally designates a materialmixing apparatusoperative to thoroughly mix fluent materials, such as various feeds andnutrient materials for animals within a hopper or mixing chamber 2including a vertically extending forward or front wall 3 and avertically extending rear wall 4 spaced from and parallel with the frontor forward wall. The mixing chamber 2 has a rounded bottom 5 and a pairof opposed sidewalls 6 and 7 extending upwardly therefrom and betweenthe front and rear walls 3 and 4.

The rounded bottom 5 is a transversely curved or arcuate portion and thesidewalls 6 and 7 have lower portions inclining or converging mutuallyinwardly as they extend downwardly for connection to the rounded bottom5 which exhibits a partially cylindrical elongated concave surfaceincluding an angle of approximately The sidewalls 6 and 7 each haveupper portions extending vertically upwardly from the downwardly andinwardly directed lower portions with the upper or upright portionsbeing spaced laterally of the rounded bottom 5.

The mixing chamber 2 is mounted on a suitable frame 8 preferably formedof lightweight high-strength structural members, such as angles,channels, beams, and the like, secured to the rounded bottom 5 and thesidewalls 6 and 7 to maintain said walls in fixed relative relationthereby producing a substantially rigid structure adapted to be suitablysecured on a mobile vehicle (not shown), such as a trailer or truck,

without danger of warpage during transportation and operation of theapparatus 1.

An agitator 10 is mounted in a lower portion of the mixing chamber 2 andadjacent the rounded bottom 5. The agitator 10 extends between and isrotatably mounted bn the front and rear walls 3 and 4 and the agitator10 is operative to thoroughly mix fluent materials having differentphysical characteristics, such as weight, size, viscosity, cohesivenessand the like, to form a thoroughly homogenous feeding ration for farmanimals.

The agitator 10 includes an elongated horizontally extending shaft 11preferably hollow for lightness of weight and hav ing end closures orplugs 12 and 13 rigidly secured in the opposite ends thereof. Shaftextensions 14 and 15 extend from the plugs or end enclosures l2 and 13respectively and through the front and rear walls 3 and 4 for operativeconnection to drive means, as later described.

The shaft extensions 14 and 15 are rotatably supported on the front andrear walls 3 and 4 respectively and portions of the frame 8.

In the illustrated structure, suitable supports, such as a pair ofspaced, ball-bearing pillow blocks 16 and 17 rotatably support the shaftextensions 14 and 15 respectively with one pillow block I6 being mountedon the front wall 3 and the other pillow block 16 being mounted on aportion of the frame 8 for rotatably supporting the shaft extension I4and one pillow block 17 being mounted on the rear wall 4 and the otherpillow block 17 being mounted on the frame 8 for rotatably supportingthe shaft extension 15 and thereby the agitator 10 within the mixingchamber 2 and adjacent the rounded bottom 5.

The agitator I0 is adapted to operate submerged beneath a mass ofmaterials to be mixed and to raise and move a portion of the materialstoward the front wall 4 and to move a portion of the materials towardthe rounded bottom 5 and the rear wall 4 thereby thoroughly mixing thematerial within the mixing chamber 2.

In the illustrated structure, the agitator 10 has a plurality ofupwardly and forwardly directed paddles l8 and a plurality of downwardlyand rearwardly directed paddles 19 to effect a thorough mixing of thematerials within the mixing chamber 2. A plurality of arms 20 aremounted on the elongated shaft 11 and extend radially outwardlytherefrom and each of the arms 20 has one of the upwardly and forwardlydirected paddles secured to the free end thereof. The arms 20 arelongitudinally spaced along the elongated shaft 11 and circumferentiallyspaced thereabout whereby the upwardly and forwardly directed paddles 18are arranged in a spiral or helical pattern about the elongated shaft11.

A like plurality of arms 21 are mounted on the elongated shaft 11 inopposed relation with the arms 20 for supporting the downwardly andrearwardly directed paddles 19 on the free ends thereof.

it is desirable to position the upwardly and forwardly directed paddles18 and the downwardly and rearwardly directed paddles 19 to prevent themixing action effected by the paddles 18 from being blocked orrestricted by the mixing action of the paddles 19 yet have the paddles19 block a portion of materials moved by the paddles 18 to effect acomplete and thorough blending of said materials, therefore, the arms 21are shorter than the arms 20, such as in the nature of up to 6 inchesshorter whereby the downwardly and rearwardly directed paddles 19 eachhave an outer peripheral edge 22 thereof spaced radially inwardly of anouter peripheral edge 23 of the upwardly and forwardly directed paddles18. The additional length of the arms 20 provides a minimum clearancebetween the outer peripheral edges 23 of the paddles l8 and the roundedbottom and adjacent portions of the sidewalls 6 and 7 to thereby raiseheavy resistant materials from the bottom of the chamber 2 and effectuniform blending with the entire batchv The upwardly and forwardlydirected paddles 18 each have a surface area in the nature of I40percent to 160 percent ofa surface area of the downwardly and rearwardlydirected paddles 19 to effect a positive movement of the materialswithin the mixing chamber 2 toward the forward or front wall 3 andtoward an upper surface of the mass of materials to be mixed.

The upwardly and forwardly directed paddles l8 and the downwardly andrearwardly directed paddles 19 are each disposed at an acute angle witha longitudinal axis of the elongated shaft 11, such as in the nature of40 to 50 whereby the positioning, relative size, and disposition of thepaddles l8 and 19 is effective to thoroughly mix the materials withinthe mixing chamber 2 when the elongated shaft 11 is rotated.

A pair of side conveyors, such as augers or feed screws 24 and 25,extend between the forward or front wall 3 and the rear wall 4 and haveopposite ends rotatably mounted thereon for moving materials adjacentthe surface of the mass of materials from the front wall 3 toward therear wall 4 and toward the agitator to thereby effect a continuousthorough mixing of the materials within the mixing chamber 2. The augersor screw conveyors 24 and 25 are above or upwardly of and laterallyspaced from the agitator l0 and adjacent the sidewalls 6 and 7respectively. The augers or feed screws 24 and 25 include elongatedshafts 26 and 27 respectively extending parallel with the elongatedshaft 11 of the agitator 10. The augers or screw conveyors 24 and 25have helical flights 28 and 29 respectively secured to the elongatedshafts 26 and 27 with one end 30 and 31 respectively thereof terminatingadjacent the front or forward wall 3 and the other ends 32 and 33 of theflights 28 and 29 respectively terminate in spaced relation with therear wall 4 forming areas 34 and 35 respectively of material directionreversal where the material is delivered to the agitator 10 with theagitator moving the material toward the forward wall 3.

The augers or feed screws 24 and 25 operate partially submerged in themass of materials to be mixed with edge portions or outer peripheries 36and 37 of the flights 28 and 29 respectively below an upper surface ofthe mass of materials whereby rotation of the augers or feed screws 24and 25 effects movement of the materials along the surface of the masstoward the rear wall 4 and the rear portion of the agitator 10.

Elongated blades 40 and 41 each have one end secured to the elongatedshafts 26 and 27 respectively and are positioned between the ends 32 and33 of the flights 28 and 29 and the rear wall 4 respectively for movingthrough material adjacent the rear wall 4 and for effectively deliveringsaid materials to the agitator 10 for movement toward the front orforward wall 3 The elongated shafts 26 and 27 extend through the forwardor front wall 3 and the rear wall 4 and are suitably rotatably mountedthereon, such as having the ends of the elongated shaft 26 extendinginto suitable bearing supports, such as ballbearing pillow blocks 42 and43 and the ends of the elongated shaft 27 extending into suitablebearing supports, such as ballbearing pillow blocks 44 and 45 suitablymounted on exterior surfaces of the walls 3 and 4 respectively.

Rotation of the augers or feed screws 24 and 25 and rotation of theagitator 10 cooperate to continually move the materials within themixing chamber 2 in a thorough mixing action and circulating thematerials to be mixed within the mass of materials wherein the augers orfeed screws 24 and 25 circulate the material from the front or forwardwall 3 toward the rear Wall 4 and toward the agitator 10 which moves thematerial toward the front or forward wall 3 constantly blending thematerials together by operation of the paddles 18 and 19. The augers orfeed screws 24 and 25 are rotated in opposite directions for moving thematerials toward center of the chamber 2 and toward the agitator 10which is rotated at a speed faster than each of the screw conveyors. Itis also preferable to rotate the augers or feed screws 24 and 25 atdifferent speeds each below the speed of rotation of the agitator l0.

Suitable rotary speeds have been found to be in the nature of 10 to 14revolutions per minute for one of the screw conveyors, for example,auger or screw conveyor 24, and a rotary speed in the nature of 13 to [7revolutions per minute for the other screw conveyor 25 and rotation ofthe agitator 10 at a speed in the nature of 14 to 18 revolutions perminute particularly with the rotation of the auger or screw conveyor 24being at a slower speed than the rotation of the auger or screw conveyor25 which also rotates at a slower speed than the agitator 10 therebyeffecting a continuous and thorough circulation of the materials withinthe mixing chamber 2.

Suitable drive means are operatively connected to the agitator l0 and tothe screw conveyors or augers 24 and 25 to rotate same and thoroughlyblend the mass of materials within the mixing chamber 2 and in theillustrated structure, a suitable prime mover, such as an internalcombustion gasoline engine, when the material-mixing apparatus 1 ismounted on a trailer and a power takeoff when the apparatus 1 is mountedon a truck, said prime mover being operative to rotate the elongatedshaft 11 by suitable transmission and speed reduction means. Forexample, the power takeoff is operative to drive a suitable chain 46engaging a sprocket 47 secured to a shaft 48 which is rotatably mountedon the frame 8. The shaft 48 has a sprocket 49 secured thereon androtating therewith for forming an input of a speed-reducing systemincluding a sprocket chain 50 engaged with a sprocket wheel 51 securedto a shaft 52 rotatably mounted on the frame 8. A sprocket wheel 53 issecured to the shaft 52 and rotatable therewith and a chain 54 extendsbetween the sprocket 53 and a sprocket 55 secured on the shaft extension14 of the elongated shaft 11 whereby rotation of the sprocket 55 effectsrotation of the agitator 10 and the input speed of the power takeoff isconsiderably reduced while the input torque is considerably increased.

A sprocket 56 is secured on the shaft extension 15 of the elongatedshaft 11 adjacent an exterior surface of the rear wall 4 and a chain 57engages the sprocket 56 and extends between and engages a sprocket 58 ofa portion of the elongated shaft 26 extending exteriorally ofthe rearwall 4. A second sprocket 59 is secured on the shaft extension 15 and isengaged by a chain 60 extending between and engaging the sprocket 59 anda sprocket 61 secured to a portion of the elongated shaft 27exteriorally of the rear wall 4. The sprockets 56 and 59 secured to theshaft extension 15 are the same size and have the same number of teethand the sprockets 58 and 61 secured on the elongated shafts 26 and 27respectively are different sizes whereby the augers or feed screws 24and 25 are driven at different speeds and each at a speed slower thanthat of the agitator 10.

Material is discharged from the mixing chamber 2 through a materialdischarge opening or port 62 provided in one of the sidewalls, forexample sidewall 6, adjacent the rounded bottom 5 and adjacent theforward or front wall 3. An outlet door 63 is slidably retained againstthe sidewall 6 by means of suitable guide runners 64 and normally closesthe discharge port 62, for example, during periods of receivingmaterials within the mixing chamber 2 and mixing same therein. When itis desired to discharge materials from the mixing chamber 2, the door 63is opened by any suitable means, such as rotation of a shaft 65 having aplurality of longitudinally spaced gears 66 secured thereon androtatable therewith and each engageable with a suitable track 67 formedin or secured to an exterior surface of the outlet door 63. Thedischarge port 62 has a chute 68 surrounding same to guide the materialsflowing through the discharge port 63 into a suitable receptacle orconveyor (not shown).

In operation of a material-mixing apparatus constructed as illustratedand described, the material to be mixed is dumped into the hopper ormixing chamber 2 and the prime mover is started to rotate the agitator 1and the augers or feed screws 24 and 25 at the relative speedspreviously described. The agitator 10 is rotated to move the paddles l8and 19 in circumferential paths around the shaft 11 whereby the upwardlyand forwardly directed paddles l8 raise and lower the material whilemoving same toward the forward or front wall 3 and the downwardly andrearwardly directed paddles 19 raise and lower the material while movingsame toward the rear wall 4 with the overall movement effected by theagitator 10 being toward the front or forward wall 3. The materialresting adjacent the augers or screw conveyors 24 and 25 is urged towardthe rear wall 4 and tends to accumulate in the areas 34 and 35. Theblades 40 and 4] prevent the material from packing against the rear wall4 and generally tend to keep the mass constantly in motion. The agitator10 operating at a speed faster than each of the augers or feed screws 24and 25 tends to pull a volume of material equal to that delivered by theaugers or feed screws 24 and 25 toward the forward or front wall 3. Therelative motion of the streams of material with portions moving towardthe rear wall 4 and portions simultaneously moving toward the forward orfront wall 3 creates crosscurrents and eddies within the material whichtends to produce a thorough and complete intermixing thereof.

The materials below the screw conveyors 24 and 25 and laterally of theagitator 10 are moved by gravity into voids within the mass of materialscreated by'movement of the paddles l8 and 19 through the mass ofmaterials to fill said voids. As the material is drawn or moved towardthe forward or front wall 3 by the agitator 10, it reaches an areawherein the outer peripheries or edge portions 36 and 37 of the flightsof the augers or screw conveyors 24 and 25 tend to urge the material inthe opposite direction wherein the material is urged upwardly anddownwardly the the rotation of the upwardly and forwardly directedpaddles 18 thereby creating flow disturbances of substantially highturbulence wherein the material is crowded or forced upwardly intocontact with the outer peripheries or edge portions 36 and 37 of theaugers or feed screws 24 and 25 which urge the material toward the rearwall 4 to repeat the mixing cycle.

The material is moved toward the forward or front wall 3 by the agitatorl0 and the material below the surface is thoroughly mixed and thus, thismakes an ideal location for the discharge opening or port 62 throughwhich the mixed material may be discharged. it is noted that due to thedirection of rotation of the augers or screw conveyors 24 and 25, thereis no tendency for material to pack against the forward wall 3 and anytendency of the material to pack at the rear wall 4 is thwarted by theaction of the elongated blades 40 and 41.

The material mixing apparatus ll has been found to operate efficientlywith either small or large quantities of materials to be mixed. A loadwhich is so small as to not reach the levels of the side augers or feedscrews 24 and 25 is effectively intermixed by operation of the paddlesl8 and 19 during rotation of the agitator 10.

It is to be understood that while I have illustrated and described oneform of my invention, it is not to be limited to the specific form orarrangement of parts herein described and shown.

What I claim and desire to secure by Letters Patent is:

l. A material-mixing apparatus comprising:

a. a mixing chamber adapted to contain materials to be mixed, saidmixing chamber being defined by a rounded bottom and opposed sidewallsextending upwardly therefrom and and spaced front and rear wallsconnected with said bottom and sidewalls; an agitator in the mixingchamber and adapted to operate submerged beneath a mass of materials tobe mixed, said agitator being rotatably mounted adjacent said roundedbottom and having a plurality of upwardly and forwardly directed paddlesand a plurality of downwardly and rearwardly directed paddles;

c. a screw conveyor adjacent each of said sidewalls, said screwconveyors each being positioned at a higher level than said agitator andhaving edge portions of a flight thereof below an upper surface of themass of materials; and

d. drive means operatively connected to said agitator and to each ofsaid screw conveyors to rotate same and blend said mass of materials.

2. A material-mixing apparatus as set forth in claim 1 wherein saidupwardly and forwardly directed paddles each have a surface area in thenature of to percent of a surface area of said downwardly and rearwardlydirected paddles.

3. A material-mixing apparatus as set forth in claim 2 wherein:

a. said screw conveyors are rotated in opposite directions for movingthe materials toward said agitator; and

b. said agitator is rotated at a speed faster than each of said screwconveyors.

, 4. A material-mixing apparatus as set forth in claim 3 wherein:

a. said upwardly and forwardly directed paddles each have a surface areain the nature of I40 to 160 percent of a surface area of said downwardlyand rearwardly directed paddles;

b. said downwardly and rearwardly directed paddles each have an outerperipheral edge thereof spaced radially inwardly of outer peripheraledges of said upwardly and forwardly directed paddles;

c. said agitator has an elongated shaft with said first plurality ofpaddles and said second plurality of paddles longitudinally spacedtherealong with said upwardly and forwardly directed paddles beingarranged in a helical pattern about said shaft; and

d. said downwardly and rearwardly directed paddles each have an outerperipheral edge thereof spaced radially inwardly of outer peripheraledges of said upwardly and forwardly directed paddles.

5. A material-mixing apparatus as set forth in claim 4 wherein:

a. one of said screw conveyors is rotated at a speed in the nature of 10to 14 revolutions per minute;

b. the other of said screw conveyors is rotated at a speed in the natureof l3 to 17 revolutions per minute; and

c. said agitator is rotated at a speed in the nature of 14 to 18revolutions per minute.

6. A material-mixing apparatus as set forth in claim 1 wherein saidagitator includes:

a. an elongated shaft having opposite ends thereof rotatably mounted onsaid end walls;

b. a first plurality of arms extending outwardly from said elongatedshaft and each having one of said upwardly and forwardly directedpaddles secured to a free end thereof; and

c. a second plurality of arms extending outwardly from said elongatedshaft and each having one of said downwardly and rearwardly directedpaddles secured to a free end thereof, said downwardly and rearwardlydirected paddles each having an outer peripheral edge thereof spacedradially inwardly of outer peripheral edges of said upwardly andforwardly directed paddles.

7. A material-mixing apparatus as set forth in claim 6 wherein:

a. said upwardly and forwardly directed paddles are disposed at an acuteangle with a longitudinal axis of said elongated shaft whereby rotationof said upwardly and forwardly directed paddles is effective to raiseand move a portion of said materials toward the front end wall; and

b. said downwardly and rearwardly directed paddles are disposed at anacute angle with a longitudinal axis of said elongated shaft wherebyrotation of said downwardly and rearwardly directed paddles is effectiveto move a portion of said materials toward the rounded bottom and therear end wall.

8. A material-mixing apparatus as set forth in claim 1 wherein saidagitator has an elongated shaft with said first plurality of paddles andsaid second plurality of paddles longitudinally spaced therealong andsaid upwardly and forwardly directed paddles are arranged in a helicalpattern about said shaft.

9. A material-mixing apparatus as set forth in claim 1 wherein saiddownwardly and rearwardly directed paddles each have an outer peripheraledge thereof spaced radially inwardly of outer peripheral edges of saidupwardly and forwardly directed paddles.

10. A material-mixing apparatus as set forth in claim 1 wherein:

a. said upwardly and forwardly directed paddles each have a surface areain the nature of I40 to l60 percent of a surface area of said downwardlyand rearwardly directed paddles; and

b. said downwardly and rearwardly directed paddles each have an outerperipheral edge thereof spaced radially inwardly of outer peripheraledges ofsaid upwardly and forwardly directed paddles.

11. A material-mixing apparatus comprising:

a. a mixing chamber adapted to contain materials to be mixed, saidmixing chamber being defined by a rounded bottom and opposed sidewallsextending upwardly therefrom and spaced front and rear end wallsconnected with said bottom and sidewalls;

b. an agitator in the mixing chamber and adapted to operate submergedbeneath a mass of materials to be mixed, said agitator being rotatablymounted adjacent said rounded bottom and having an elongated shaft and afirst plurality of upwardly and forwardly directed paddles and a secondplurality of downwardly and rearwardly directed paddles -'mounted onsaid shaft and longitudinally spaced therealong, said upwardly andforwardly directed paddles each having a surface area in the nature ofI40 to percent of a surface area of said downwardly and rearwardlydirected paddles, said upwardly and forwardly directed paddles beingarranged in a helical pattern about said elongated shaft;

a screw conveyor adjacent each of said sidewalls, said screw conveyorseach being positioned above said agitator and having edge portions of aflight thereof below an upper surface of the mass of materials, saidscrew conveyors being rotated in opposite directions for moving thematerials toward said agitator; and d. drive means operatively connectedto said agitator and to each of said screw conveyors to rotate same andblend said mass of materials, said drive means being operative to rotatesaid agitator at a speed faster than each of said screw conveyors.

1. A material-mixing apparatus comprising: a. a mixing chamber adaptedto contain materials to be mixed, said mixing chamber being defined by arounded bottom and opposed sidewalls extending upwardly therefrom andand spaced front and rear walls connected with said bottom andsidewalls; b. an agitator in the mixing chamber and adapted to operatesubmerged beneath a mass of materials to be mixed, said agitator beingrotatably mounted adjacent said rounded bottom and having a plurality ofupwardly and forwardly directed paddles and a plurality of downwardlyand rearwardly directed paddles; c. a screw conveyor adjacent each ofsaid sidewalls, said screw conveyors each being positioned at a higherlevel than said agitator and having edge portions of a flight thereofbelow an upper surface of the mass of materials; and d. drive meansoperatively connected to said agitator and to each of said screwconveyors to rotate same and blend said mass of materials.
 2. Amaterial-mixing apparatus as set forth in claim 1 wherein said upwardlyand forwardly directed paddles each have a surface area in the nature of140 to 160 percent of a surface area of said downwardly and rearwardlydirected paddles.
 3. A material-mixing apparatus as set forth in claim 2wherein: a. said screw conveyors are rotated in opposite directions formoving the materials toward said agitator; and b. said agitator isrotated at a speed faster than each of said screw conveyors.
 4. Amaterial-mixing apparatus as set forth in claim 3 wherein: a. saidupwardly and forwardly directed paddles each have a surface area in thenature of 140 to 160 percent of a surface area of said downwardly andrearwardly directed paddles; b. said downwardly and rearwardly directedpaddles each have an outer peripheral edge thereof spaced radiallyinwardly of outer peripheral edges of said upwardly and forwardlydirected paddles; c. said agitator has an elongated shaft with saidfirst plurality of paddles and said second plurality of paddleslongitudinally spaced therealong with said upwardly and forwardlydirected paddles being arranged in a helical pattern about said shaft;and d. said downwardly and rearwardly directed paddles each have anouter peripheral edge thereof spaced radially inwardly of outerperipheral edges of said upwardly and forwardly directed paddles.
 5. Amaterial-mixing apparatus as set forth in claim 4 wherein: a. one ofsaid screw conveyors is rotated at a speed in the nature of 10 to 14revolutions per minute; b. the other of said screw conveyors is rotatedat a speed in the nature of 13 to 17 revolutions per minute; and c. saidagitator is rotated at a speed in the nature of 14 to 18 revolutions perminute.
 6. A material-mixing apparatus as set forth in claim 1 whereinsaid agitator includes: a. an elongated shaft having opposite endsthereof rotatably mounted on said end walls; b. a first plurality ofarms extending outwardly from said elongated shaft and each having oneof said upwardly and forwardly directed paddles secured to a free endthereof; and c. a second plurality of arms extending outwardly from saidelongated shaft and each having one of said downwardly and rearwardlydirected paddles secured to a free end thereof, said downwardly andrearwardly directed paddles each having an outer peripheral edge thereofspaced radially inwardly of outer peripheral edges of said upwardly andforwardly directed paddles.
 7. A material-mixing apparatus as set forthin claim 6 wherein: a. said upwardly and forwardly directed paddles aredisposed at an acute angle with a longitudinal axis of said elongatedshaft whereby rotation of said upwardly and forwardly directed paddlesis effective to raise and move a portion of said materials toward thefront end wall; and b. said downwardly and rearwardly directed paddlesare disposed at an acute angle with a longitudinal axis of saidelongated shaft whereby rotation of said downwardly and rearwardlydirected paddles is effective to move a portion of said materials towardthe rounded bottom and the rear end wall.
 8. A material-mixing apparatusas set forth in claim 1 wherein said agitator has an elongated shaftwith said first plurality of paddles and said second plurality ofpaddles longitudinally spaced therealong and said upwardly and forwardlydirected paddles are arranged in a helical pattern about said shaft. 9.A material-mixing apparatus as set forth in claim 1 wherein saiddownwardly and rearwardly directed paddles each have an outer peripheraledge thereof spaced radially inwardly of outer peripheral edges of saidupwardly and forwardly directed paddles.
 10. A material-mixing apparatusas set forth in claim 1 wherein: a. said upwardly and forwardly directedpaddles each have a surface area in the nature of 140 to 160 percent ofa surface area of said downwardly and rearwardly directed paddles; andb. said downwardly and rearwardly directed paddleS each have an outerperipheral edge thereof spaced radially inwardly of outer peripheraledges of said upwardly and forwardly directed paddles.
 11. Amaterial-mixing apparatus comprising: a. a mixing chamber adapted tocontain materials to be mixed, said mixing chamber being defined by arounded bottom and opposed sidewalls extending upwardly therefrom andspaced front and rear end walls connected with said bottom andsidewalls; b. an agitator in the mixing chamber and adapted to operatesubmerged beneath a mass of materials to be mixed, said agitator beingrotatably mounted adjacent said rounded bottom and having an elongatedshaft and a first plurality of upwardly and forwardly directed paddlesand a second plurality of downwardly and rearwardly directed paddlesmounted on said shaft and longitudinally spaced therealong, saidupwardly and forwardly directed paddles each having a surface area inthe nature of 140 to 160 percent of a surface area of said downwardlyand rearwardly directed paddles, said upwardly and forwardly directedpaddles being arranged in a helical pattern about said elongated shaft;c. a screw conveyor adjacent each of said sidewalls, said screwconveyors each being positioned above said agitator and having edgeportions of a flight thereof below an upper surface of the mass ofmaterials, said screw conveyors being rotated in opposite directions formoving the materials toward said agitator; and d. drive meansoperatively connected to said agitator and to each of said screwconveyors to rotate same and blend said mass of materials, said drivemeans being operative to rotate said agitator at a speed faster thaneach of said screw conveyors.